1// Copyright 2013 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
6#define V8_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
7
8#include "src/macro-assembler.h"
9
10#include "src/arm64/assembler-arm64.h"
11#include "src/arm64/assembler-arm64-inl.h"
12
13namespace v8 {
14namespace internal {
15
16
17#ifndef V8_INTERPRETED_REGEXP
18class RegExpMacroAssemblerARM64: public NativeRegExpMacroAssembler {
19 public:
20  RegExpMacroAssemblerARM64(Mode mode, int registers_to_save, Zone* zone);
21  virtual ~RegExpMacroAssemblerARM64();
22  virtual int stack_limit_slack();
23  virtual void AdvanceCurrentPosition(int by);
24  virtual void AdvanceRegister(int reg, int by);
25  virtual void Backtrack();
26  virtual void Bind(Label* label);
27  virtual void CheckAtStart(Label* on_at_start);
28  virtual void CheckCharacter(unsigned c, Label* on_equal);
29  virtual void CheckCharacterAfterAnd(unsigned c,
30                                      unsigned mask,
31                                      Label* on_equal);
32  virtual void CheckCharacterGT(uc16 limit, Label* on_greater);
33  virtual void CheckCharacterLT(uc16 limit, Label* on_less);
34  virtual void CheckCharacters(Vector<const uc16> str,
35                               int cp_offset,
36                               Label* on_failure,
37                               bool check_end_of_string);
38  // A "greedy loop" is a loop that is both greedy and with a simple
39  // body. It has a particularly simple implementation.
40  virtual void CheckGreedyLoop(Label* on_tos_equals_current_position);
41  virtual void CheckNotAtStart(Label* on_not_at_start);
42  virtual void CheckNotBackReference(int start_reg, Label* on_no_match);
43  virtual void CheckNotBackReferenceIgnoreCase(int start_reg,
44                                               Label* on_no_match);
45  virtual void CheckNotCharacter(unsigned c, Label* on_not_equal);
46  virtual void CheckNotCharacterAfterAnd(unsigned c,
47                                         unsigned mask,
48                                         Label* on_not_equal);
49  virtual void CheckNotCharacterAfterMinusAnd(uc16 c,
50                                              uc16 minus,
51                                              uc16 mask,
52                                              Label* on_not_equal);
53  virtual void CheckCharacterInRange(uc16 from,
54                                     uc16 to,
55                                     Label* on_in_range);
56  virtual void CheckCharacterNotInRange(uc16 from,
57                                        uc16 to,
58                                        Label* on_not_in_range);
59  virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set);
60
61  // Checks whether the given offset from the current position is before
62  // the end of the string.
63  virtual void CheckPosition(int cp_offset, Label* on_outside_input);
64  virtual bool CheckSpecialCharacterClass(uc16 type,
65                                          Label* on_no_match);
66  virtual void Fail();
67  virtual Handle<HeapObject> GetCode(Handle<String> source);
68  virtual void GoTo(Label* label);
69  virtual void IfRegisterGE(int reg, int comparand, Label* if_ge);
70  virtual void IfRegisterLT(int reg, int comparand, Label* if_lt);
71  virtual void IfRegisterEqPos(int reg, Label* if_eq);
72  virtual IrregexpImplementation Implementation();
73  virtual void LoadCurrentCharacter(int cp_offset,
74                                    Label* on_end_of_input,
75                                    bool check_bounds = true,
76                                    int characters = 1);
77  virtual void PopCurrentPosition();
78  virtual void PopRegister(int register_index);
79  virtual void PushBacktrack(Label* label);
80  virtual void PushCurrentPosition();
81  virtual void PushRegister(int register_index,
82                            StackCheckFlag check_stack_limit);
83  virtual void ReadCurrentPositionFromRegister(int reg);
84  virtual void ReadStackPointerFromRegister(int reg);
85  virtual void SetCurrentPositionFromEnd(int by);
86  virtual void SetRegister(int register_index, int to);
87  virtual bool Succeed();
88  virtual void WriteCurrentPositionToRegister(int reg, int cp_offset);
89  virtual void ClearRegisters(int reg_from, int reg_to);
90  virtual void WriteStackPointerToRegister(int reg);
91  virtual bool CanReadUnaligned();
92
93  // Called from RegExp if the stack-guard is triggered.
94  // If the code object is relocated, the return address is fixed before
95  // returning.
96  static int CheckStackGuardState(Address* return_address,
97                                  Code* re_code,
98                                  Address re_frame,
99                                  int start_offset,
100                                  const byte** input_start,
101                                  const byte** input_end);
102
103 private:
104  // Above the frame pointer - Stored registers and stack passed parameters.
105  // Callee-saved registers x19-x29, where x29 is the old frame pointer.
106  static const int kCalleeSavedRegisters = 0;
107  // Return address.
108  // It is placed above the 11 callee-saved registers.
109  static const int kReturnAddress = kCalleeSavedRegisters + 11 * kPointerSize;
110  static const int kSecondaryReturnAddress = kReturnAddress + kPointerSize;
111  // Stack parameter placed by caller.
112  static const int kIsolate = kSecondaryReturnAddress + kPointerSize;
113
114  // Below the frame pointer.
115  // Register parameters stored by setup code.
116  static const int kDirectCall = kCalleeSavedRegisters - kPointerSize;
117  static const int kStackBase = kDirectCall - kPointerSize;
118  static const int kOutputSize = kStackBase - kPointerSize;
119  static const int kInput = kOutputSize - kPointerSize;
120  // When adding local variables remember to push space for them in
121  // the frame in GetCode.
122  static const int kSuccessCounter = kInput - kPointerSize;
123  // First position register address on the stack. Following positions are
124  // below it. A position is a 32 bit value.
125  static const int kFirstRegisterOnStack = kSuccessCounter - kWRegSize;
126  // A capture is a 64 bit value holding two position.
127  static const int kFirstCaptureOnStack = kSuccessCounter - kXRegSize;
128
129  // Initial size of code buffer.
130  static const size_t kRegExpCodeSize = 1024;
131
132  // When initializing registers to a non-position value we can unroll
133  // the loop. Set the limit of registers to unroll.
134  static const int kNumRegistersToUnroll = 16;
135
136  // We are using x0 to x7 as a register cache. Each hardware register must
137  // contain one capture, that is two 32 bit registers. We can cache at most
138  // 16 registers.
139  static const int kNumCachedRegisters = 16;
140
141  // Load a number of characters at the given offset from the
142  // current position, into the current-character register.
143  void LoadCurrentCharacterUnchecked(int cp_offset, int character_count);
144
145  // Check whether preemption has been requested.
146  void CheckPreemption();
147
148  // Check whether we are exceeding the stack limit on the backtrack stack.
149  void CheckStackLimit();
150
151  // Generate a call to CheckStackGuardState.
152  void CallCheckStackGuardState(Register scratch);
153
154  // Location of a 32 bit position register.
155  MemOperand register_location(int register_index);
156
157  // Location of a 64 bit capture, combining two position registers.
158  MemOperand capture_location(int register_index, Register scratch);
159
160  // Register holding the current input position as negative offset from
161  // the end of the string.
162  Register current_input_offset() { return w21; }
163
164  // The register containing the current character after LoadCurrentCharacter.
165  Register current_character() { return w22; }
166
167  // Register holding address of the end of the input string.
168  Register input_end() { return x25; }
169
170  // Register holding address of the start of the input string.
171  Register input_start() { return x26; }
172
173  // Register holding the offset from the start of the string where we should
174  // start matching.
175  Register start_offset() { return w27; }
176
177  // Pointer to the output array's first element.
178  Register output_array() { return x28; }
179
180  // Register holding the frame address. Local variables, parameters and
181  // regexp registers are addressed relative to this.
182  Register frame_pointer() { return fp; }
183
184  // The register containing the backtrack stack top. Provides a meaningful
185  // name to the register.
186  Register backtrack_stackpointer() { return x23; }
187
188  // Register holding pointer to the current code object.
189  Register code_pointer() { return x20; }
190
191  // Register holding the value used for clearing capture registers.
192  Register non_position_value() { return w24; }
193  // The top 32 bit of this register is used to store this value
194  // twice. This is used for clearing more than one register at a time.
195  Register twice_non_position_value() { return x24; }
196
197  // Byte size of chars in the string to match (decided by the Mode argument)
198  int char_size() { return static_cast<int>(mode_); }
199
200  // Equivalent to a conditional branch to the label, unless the label
201  // is NULL, in which case it is a conditional Backtrack.
202  void BranchOrBacktrack(Condition condition, Label* to);
203
204  // Compares reg against immmediate before calling BranchOrBacktrack.
205  // It makes use of the Cbz and Cbnz instructions.
206  void CompareAndBranchOrBacktrack(Register reg,
207                                   int immediate,
208                                   Condition condition,
209                                   Label* to);
210
211  inline void CallIf(Label* to, Condition condition);
212
213  // Save and restore the link register on the stack in a way that
214  // is GC-safe.
215  inline void SaveLinkRegister();
216  inline void RestoreLinkRegister();
217
218  // Pushes the value of a register on the backtrack stack. Decrements the
219  // stack pointer by a word size and stores the register's value there.
220  inline void Push(Register source);
221
222  // Pops a value from the backtrack stack. Reads the word at the stack pointer
223  // and increments it by a word size.
224  inline void Pop(Register target);
225
226  // This state indicates where the register actually is.
227  enum RegisterState {
228    STACKED,     // Resides in memory.
229    CACHED_LSW,  // Least Significant Word of a 64 bit hardware register.
230    CACHED_MSW   // Most Significant Word of a 64 bit hardware register.
231  };
232
233  RegisterState GetRegisterState(int register_index) {
234    DCHECK(register_index >= 0);
235    if (register_index >= kNumCachedRegisters) {
236      return STACKED;
237    } else {
238      if ((register_index % 2) == 0) {
239        return CACHED_LSW;
240      } else {
241        return CACHED_MSW;
242      }
243    }
244  }
245
246  // Store helper that takes the state of the register into account.
247  inline void StoreRegister(int register_index, Register source);
248
249  // Returns a hardware W register that holds the value of the capture
250  // register.
251  //
252  // This function will try to use an existing cache register (w0-w7) for the
253  // result. Otherwise, it will load the value into maybe_result.
254  //
255  // If the returned register is anything other than maybe_result, calling code
256  // must not write to it.
257  inline Register GetRegister(int register_index, Register maybe_result);
258
259  // Returns the harware register (x0-x7) holding the value of the capture
260  // register.
261  // This assumes that the state of the register is not STACKED.
262  inline Register GetCachedRegister(int register_index);
263
264  Isolate* isolate() const { return masm_->isolate(); }
265
266  MacroAssembler* masm_;
267
268  // Which mode to generate code for (LATIN1 or UC16).
269  Mode mode_;
270
271  // One greater than maximal register index actually used.
272  int num_registers_;
273
274  // Number of registers to output at the end (the saved registers
275  // are always 0..num_saved_registers_-1)
276  int num_saved_registers_;
277
278  // Labels used internally.
279  Label entry_label_;
280  Label start_label_;
281  Label success_label_;
282  Label backtrack_label_;
283  Label exit_label_;
284  Label check_preempt_label_;
285  Label stack_overflow_label_;
286};
287
288#endif  // V8_INTERPRETED_REGEXP
289
290
291}}  // namespace v8::internal
292
293#endif  // V8_ARM64_REGEXP_MACRO_ASSEMBLER_ARM64_H_
294